Maven: A Developer's Notebook

Creating Custom Top-Level Goals

Now let's build the QOTD web application using our master project. Hold on! What does it mean to build the QOTD web application? Each subproject has its own definition of build: for the core subproject it means calling the jar:install goal, for the web subproject it means calling the war:install goal, etc. You need to define some common goals in your subprojects that you can call from your master project.

How do I do that?

You can do this easily, by creating a maven.xml file in each subproject and defining a custom goal in there. Let's call this goal qotd:build. Here's what you would put in the core/maven.xml file:

<?xml version="1.0"?>
  
<project default="qotd:build">
  <goal name="qotd:build" prereqs="jar:install"/>
</project>

The same applies for the other subprojects. For example, for the web subproject, you'll write:

<?xml version="1.0"?>
  
<project default="qotd:build">
  <goal name="qotd:build" prereqs="war:install"/>
</project>

Note

To manage different types of subproject builds, define the same custom goal in each subproject and use the Multiproject plug-in to execute it.

Now that each subproject has a qotd:build goal that builds it, you can also create a qotd:build goal in the master project's maven.xml file. This goal uses the Multiproject plug-in to call the qotd:build goal on all the subprojects:

<?xml version="1.0"?> <project default="qotd:build" xmlns:j="jelly:core"> <goal name="qotd:build"> <j:set var="goal" value="qotd:build"/> <attainGoal name="multiproject:goal"/> ...